The strongside linebacker (SLB) is often nicknamed "Sam" for purposes of calling a blitz. Since the strong side of the offensive team is the side on which the tight end lines up, or whichever side contains the most personnel, the strongside linebacker usually lines up across from the tight end. Often the strongside linebacker will be called upon to tackle the running back on a play, because the back will be following the tight end's block. He is most often the strongest linebacker; at the least he possesses the ability to withstand, shed, and fight off blocks from a TE or a FB blocking the backside of a pass play. The linebacker should also have strong safety abilities in pass situation to cover the tight end in man on man situations. He should also have considerable quickness to read and get into coverage in zone situations.

Weakside linebacker

The weakside linebacker, or "Will", must be the fastest of the three, because he is often the one called into pass coverage. He is also usually chasing the play from the backside, so the ability to maneuver through traffic is a necessity for Will. Will usually aligns off the line of scrimmage at the same depth as Mike. Because of his position on the weakside, Will does not often have to face large interior linemen one on one unless one is pulling. In coverage, Will often covers the back that attacks his side of the field first in man coverage, while covering the weak flat or hook/curl areas in zone coverage. In a 3-4 defense the "Will" Linebacker plays on the "weakside" of the two middle Linebacker positions and a 4th Linebacker comes in to play the weakside. Known as a "Rush", "Rover", "Jack" and/or "Buck" Linebacker, their responsibility is more pass rush based but often is called into run stop (gap control) and pass coverage.